1. Field of the Invention
This invention relates to enclosures for the packaging of items in isolation from contamination for use with sensitive items such as electronic components, and more particularly such enclosures including facilities for purging a sealed container.
2. Description of related art.
Packaging is an integral part of the transportation and delivery of products during the course of manufacturing. One important requirement for packaging has been to provide ease of handling and space efficient storage of the product free from contamination, during manufacturing, between manufacturing processes and prior to use.
An important function of such packaging is the protection of a product from contamination during the process of production or manufacturing between manufacturing steps. Such protection has become particularly critical for electronic circuit components which are often subject to damage from a wide range of environmental conditions including contamination by vapors and particles present in containers or evolved within those containers when an article is stored therein.
Maintaining clean conditions has become more important during recent years with the increase of storage and transportation of intermediate products for electronic devices which must be maintained in a clean condition when removed from the packaging for further processing. Further, the maintenance of an adequately clean manufacturing environment has led to increased manipulation of the packaging and items contained therein by automated processing equipment. Therefore, isolation structures used in such manufacturing processes must be adapted to be manipulated by such equipment in addition to providing the required types of protection for the packaged items. This adaptation often requires both the packaging and the automated equipment to be specially modified and standardized, increasing costs and reducing the generality of application of the automated equipment.
A Standard Mechanical Interface (SMIF) is described in U.S. Pat. Nos. 4,532,970 of Tullis et al for "Particle Free Dockable Interface for Integrated Circuit Processing" states at Col. 3, lines 50-64 that the SMIF box does "not utilize constantly moving filtered air to decrease particles on the IC wafer surfaces. Rather, IC cleanliness is achieved by maintaining a still-air interior environment." In summary, such SMIF interfaces are to be used with semiconductor wafers, to protect them from contaminants by preventing circulation of air about the wafers.
U.S. Pat. No. 4,724,874 of Parikh et al for "Sealable Transportable Container Having a Particle Filtering System" describes a filtering system and an air circulation system for at Col. 7, lines 57 et seq. "filtering and analyzing having an inlet . . . and an outlet . . . . Clean air or free N.sub.2 is pumped by pump P into the interior space . . . , circulated through conduit tubing . . . and then exhausted through an outlet. A filter . . . for trapping any particles in the interior space . . . is provided at the outlet . . . . Additionally the inlet could also have a filter. Each of the inlet . . . and outlet . . . are one-way valves so that unwanted fluids can not enter the first environment . . . ."
This invention is based on a realization by the inventors of a need for a simpler structure which operates more quickly, with minimal interaction instead of more elaborate mechanisms used to perform such functions in the past. It would be desirable to be able to make a quick connection and quick removal of work from the purging station where articles in an enclosed chamber are to be purged of unwanted gases, etc., during storage, when off line from a manufacturing process.
It is therefore an object of the present invention to provide a system for quickly connecting and removing a source of purging gases to an isolation structure containing an item therein from contamination by particles or vapors generated either internally or externally of the isolation structure.
Still another object of this invention is automatically disconnecting the outlets and inlets of the purging system and the exhausting system when the closed container to be purged is removed.
In accordance with this invention, a reusable isolation enclosure has a closure member carrying filters and vapor and moisture drains. Replacement of ambient environmental gases in the sealed enclosure is provided. A replacement or inert gas is provided by the gas replacement system which quickly connects to the enclosure and quickly disconnects from the enclosure. Suction cups surrounding the ends of gas connection lines form the interface to the filter membrane and form a seal with the closure member. No other mechanical connection than the suction cups is required. The outlets and inlets of the purging system and the exhausting system are automatically disconnected by a spring valve when the isolation container to be purged is removed. When the closure member of the isolation enclosure is placed upon on the purge system the weight of the package overcomes the spring force and thus opens the valves and permits the replacement gas to flow. If the empty isolation enclosure is placed on the system the weight is insufficient to open the spring actuated valve system, therefore only enclosures carrying the weight of a product will be purged by the gas replacement system.
The solution in accordance with this invention can be used in the business of providing closed containers to the semiconductor industry, and this solution has applications in other areas beyond semiconductor products.
Further in accordance with this invention, an isolation structure includes a) a shell having a opening, b) a closure member dimensioned to be received within the opening, the closure member including i) a closure member body having an outer periphery and a resilient seal on the outer periphery of the closure member body, ii) a gas exchange system for the structure including (1) a gas inlet port for the structure having an inlet filter membrane, and (2) a gas outlet port for the structure having an outlet filter membrane, e) quick connection supply means for supplying a source of gas to be introduced to purge the chamber by means of a quick mechanical connection, f) the supply means including i) a spring actuated inlet valve with a self-sealing interface, and ii) a spring actuated outlet valve with a self-sealing interface adapted to for providing quick connection to the gas inlet port and the gas outlet port respectively. Preferably the means for locating at least one of the front plate and the back plate includes a pair of breather bodies containing the filter membranes; and the front plate has at least one aperture formed therein.
Preferably the closure member includes means for locating at least one of the front plate and the back plate relative to the backbone further includes a breather body.
In another aspect of the invention, a gas exchange system for a sealed chamber comprises the chamber, a) an inlet filter membrane in the wall of the chamber, b) an outlet filter membrane in the wall of the chamber, c) supply means having a source of a gas to be exchanged into the chamber, and d) an inlet line and an outlet line each being connected to the the supply means and each terminating in a self sealing connection to the inlet or outlet filter respectively.
In still another aspect of this invention, an isolation structure includes a) a shell having a opening, b) a closure member dimensioned to be received within the opening, the closure member including i) a closure member body having an outer periphery and a resilient seal on the outer periphery of the closure member body, ii) a gas exchange system for the structure including a gas port for the structure having a filter membrane, the port extending from the exterior to the interior of the structure, c) quick connection supply means including a spring actuated valve with a self-sealing interface adapted for providing quick connection to the gas port in response to the presence of an article in the chamber, preferably as a function of the contents of the chamber exceeding a predetermined weight. In short, the quick connection of the gas port is responsive to the weight of the article in the chamber.